2/12 HS Physics update and homework due 2/19

Hi folks,

Today we got a bit deeper in our journey to understanding energy by getting into the concept of work.  We will be getting a bit deeper into this as we use the concept to explore simple machines next week.

For homework this week:

Read pages 103 - 110 in the text.

Do questions 1 - 5 on page 119

Also, answer the following questions.  

1.  What is the definition of work?

2.  What is the definition of power?

3.  What unit do we use for work?  

4.  What unit do we use for power?

5.  What is a Newton?

6.  What is potential energy?

7.  Describe a scenario where energy is changing forms at least 4 times (like the toaster scenario we did last week).

8.  How is work different from power?

9.  If a forklift is replaced with a new forklift that has twice the power, how much greater a load can it lift in the same amount of time?  If it lifts the same load, how much faster can it operate?

10.  Today we went outside and pushed my car.  What did that have to do with work?  What did it have to do with power?

11.  What is kinetic energy?

12.  What are three examples of potential energy and how would they convert to kinetic energy?

13.  If, instead of pushing my car you pushed a wheel barrow that took 50 N to push, how far could you push that wheelbarrow if you used 500J of energy?

14.  In the formula W=FD, what is the relationship between work and force (is it inversely or directly proportional)?

15.  In the formula W=FD, what is the relationship between force and distance  (is it inversely or directly proportional)?

16.  If work stays the same but the force it takes to move an object doubles, what happens to the distance it can be moved?

17.  What is doing work on what in the following examples?  I'll do the first one for you.

a.  A person is riding a bicycle.  Answer: The person is doing work on the bicycle.

b.  A child pulling a wagon.

c.  A man is riding a horse.  (Careful)

d.  A car is braking to stop.